The good news is that I just bought a hardly used '90s era Specialized Globe 3-speed. The bike was local to me and I doubt it has been ridden more than 10 times. It has the usual rotten tires and the hub needs adjustment, but boy does it move. I was cruising around the neighborhood last night at 17-18mph without much effort.
The bad news is that I did not notice the very high "minimum insertion" line on the seatube before I bought it. I have long legs and this is only a medium frame. I need the seat at least 2 inches above the minimum line. The tube is 26 x 400 and is unusual in that the minimum insertion line is only 10 cm below the top of the post. Most posts I've seen are the opposite (10 cm into the bike at min).
So, I'm wondering is this just a funky old seatpost that I can replace with a modern part with the usual lower minimum line or does this particular post have something to do with the Globe's unusual frame. I attached a pic. As shown the seat tube juts up about 15 cm above the top tube, kind of sticks up there all by itself. I put yellow tape at the minimum line on the seat post and on the frame where the bottom of the seat tube sits at my desired ride height. So, does the long seat tube insertion help to strengthen the seat tube? If that is the case, I assume I'm done and will have to re-sell the bike. The frame is steel and beautifully assembled. As you can see the post is just below the top tube but not by more than an inch at the ride height I need. If it is not a frame issue, I will definitely buy a new post that purports to be strong enough for that ride height I need. I'm really hoping I can make this bike work for me as a daily commuter.
I'm afraid it is. If you need to raise the seat that high above the frame, then that suggests to me that you need a larger frame. If that's a medium frame, then I'd say you should be looking at a large, easily.
Yeah, the frame is too small. My inseam is 32-33 inches and I like to have 32" from the bottom bracket to the top of the seat. If I was shopping for a new bike at a shop I would get a L or maybe even an XL frame. When you buy used and local, your choices are limited. This was the first decent cheap bike I've seen locally in 2-3 months. If I wanted a Walmart mountain bike for less than $100, I would have had a dozen to pick from.
However, I think I have workable solution. The stock seat is basically a flat road seat. I put on a sprung cruiser saddle and gained another inch from that. I then lowered the seat post an inch and a half so I'm only 1.5 inches over the "min" insert line. At 175 pounds, I'm willing to live with that, about 2/3rds of the seat post is in the bike. With that I've got 31" crank to seat, not my sweet spot but pretty close.
I put some new brake pads and Specialed Fat Boys (26 x 1.25) on this morning and did 4 miles averaging 16mph without too much effort. Gears are a bit gummed-up, slipped in second on the way back so I'll have to work on that but I'm pretty satisfied with my sub-$200 investment (including brake pads and tires) so far.
I am not sure I understand your problem. It does appear that your post is very high. I think most posts have at least 2.5-inch insertion maybe more, I am guessing. Posts come in different lengths so if you are saying your tube is 400 mm perhaps you can find a post 2 inches longer than your current one.
I ride a Schwinn Wasp, which is 26 inch cruiser from the middle 1950's. They only came in one size at that time. I was able to find a much longer post than the stock one. I very much enjoy riding this bike. Check out the post.